Semiconductor memory is widely used in various electronic devices such as cellular telephones, digital cameras, personal digital assistants, medical electronics, mobile computing devices, servers, solid state drives (“SSDs”), non-mobile computing devices and other devices. Semiconductor memory may comprise non-volatile memory or volatile memory. A non-volatile memory allows information to be stored and retained even when the non-volatile memory is not connected to a source of power (e.g., a battery).
As some non-volatile memory is subjected to many program and erase cycles, performance and reliability can degrade. In some instances, blocks of non-volatile memory cells can fail causing the system to retire the block from future use. While retiring the block from future use does maintain device reliability, retiring bad blocks does reduce capacity of the memory.